Electronic Device Having Display With Curved Edges

ABSTRACT

A display may have an array of pixels. The array of pixels may have a shape such as a circular shape or other shape with a curved edge. Display driver circuitry may supply data signals to the pixels using folded vertical data lines and bisected horizontal gate lines. Each folded vertical lines may have a first segment in a left half of the array and a second segment in a right half of the display. Curved coupling segments in an inactive area of the display may be used in joining the first and second segments. Display driver circuits may be provided in top and bottom portions of the inactive area to supply data to respective top and bottom portions of the array. Gate driver output buffers may have different strengths in different rows of the array.

This application claims the benefit of provisional patent applicationNo. 62/169,453, filed Jun. 1, 2015, which is hereby incorporated byreference herein in its entirety.

BACKGROUND

This relates generally to displays, and, more particularly, to displayswith curved edges.

Electronic devices such as cellular telephones, computers, andwristwatch devices often include displays. Display driver circuitry isused to apply control signals to an array of pixels in a display. Thearray of pixels is used to display images for a user.

Pixel arrays generally have rectangular shapes and include rows andcolumns of pixels controlled by vertical and horizontal signal lines.Data lines that extend vertically through an array distribute datasignals to the pixels. Gate lines that extend horizontally through thearray are used to provide control signals to the pixels of each row.

Pixel arrays often have rectangular shapes. However, rectangular pixelarrays will not fit efficiently within a device having a circular shape.Circular displays can have bottleneck regions in which signal linesbecome crowded, leading to inefficient use of display area.

It would therefore be desirable to be able to provide improved displayssuch as circular displays or other displays with curved edges.

SUMMARY

An electronic device may have a display. The display may have an arrayof pixels. The array may have rows and columns of pixels that form anactive area for the display. The active area may have a curved edge andmay have a circular shape. A circular ring-shaped inactive area maysurround the circular active area of the display. Display drivercircuitry may overlap the inactive area. For example, curved strips ofgate driver circuitry may run along left and right portions of theinactive area.

Display driver circuitry may supply data signals to the pixels usingfolded vertical data lines. Each folded vertical lines may have a firstsegment in a left half of the array and a second segment in a right halfof the display. Horizontal gate lines may run across the vertical datalines. The horizontal gate lines may be bisected to form left and rightisolated segments in each row of the array. The gate driver circuitrymay include gate driver circuitry in the left portion of the inactivearea that supplies gate line signals to the left segments so that thesegments of the folded data lines in the left half of the array cansupply data to the pixels in the left half of the array. The gate drivercircuitry may also include gate driver circuitry in the right portion ofthe inactive area that supplies gate lines signals to the right segmentsso that the segments of the folded data lines in the right half of thearray can supply data to the pixels in the right half of the array.Curved coupling segments of the data lines that lie in the inactive areaof the display may be used in joining the first and second segments ofeach data line. Gate driver output buffers may have different strengthsin different rows of the array.

An electronic device may have portions that bend or may include flexibleprinted circuits that are bent. Serpentine lines may be used to conveydisplay signals to and from display driver circuitry in the device. Theserpentine lines may overlap a bent portion of a flexible printedcircuit or other bent substrate in a display.

Display driver circuits may be provided in top and bottom portions ofthe inactive area of a display to supply data to respective top andbottom portions of an array of pixels in the display. By spreading outthe data line paths between the top and bottom portions of the inactivearea, signal line crowding can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative electronic devicehaving a display in accordance with an embodiment.

FIG. 2 is a perspective view of an illustrative electronic device havinga display in accordance with an embodiment.

FIG. 3 is a perspective view of an illustrative electronic device havinga circular display in accordance with an embodiment.

FIG. 4 is a diagram of an illustrative array of pixels for a display inaccordance with an embodiment.

FIG. 5 is a top view of an illustrative display in accordance with anembodiment.

FIG. 6 is a top view of an illustrative pattern of gate lines and datalines that may be used in a display in accordance with an embodiment.

FIG. 7 is a top view of another illustrative pattern of gate lines anddata lines that may be used in a display in accordance with anembodiment.

FIG. 8 is a top view of an illustrative electronic device having adisplay in accordance with an embodiment.

FIG. 9 is a perspective view of an illustrative bent substrate havingtraces that resist cracking in accordance with an embodiment.

FIG. 10 is a top view of an illustrative set of serpentine traces thatresist cracking when bent in accordance with an embodiment.

FIG. 11 is a top view of another illustrative set of serpentine tracesthat resist cracking when bent in accordance with an embodiment.

FIG. 12 is a diagram of illustrative gate driver circuitry in accordancewith an embodiment.

FIG. 13 is a diagram of illustrative gate driver circuitry with outputbuffers that increase in size as a function of increasing row size in adisplay in accordance with an embodiment.

DETAILED DESCRIPTION

Electronic devices may be provided with displays. The displays may havecircular shapes or other shapes with curved edges. A schematic diagramof an illustrative electronic device with a display is shown in FIG. 1.Device 10 of FIG. 1 may be a computing device such as a laptop computer,a computer monitor containing an embedded computer, a tablet computer, acellular telephone, a media player, or other handheld or portableelectronic device, a smaller device such as a wrist-watch device (e.g.,a watch with a wrist strap), a pendant device, a headphone or earpiecedevice, a device embedded in eyeglasses or other equipment worn on auser's head, or other wearable or miniature device, a television, acomputer display that does not contain an embedded computer, a gamingdevice, a navigation device, an embedded system such as a system inwhich electronic equipment with a display is mounted in a kiosk orautomobile, equipment that implements the functionality of two or moreof these devices, or other electronic equipment.

As shown in FIG. 1, electronic device 10 may have control circuitry 20.Control circuitry 20 may include storage and processing circuitry forsupporting the operation of device 10. The storage and processingcircuitry may include storage such as hard disk drive storage,nonvolatile memory (e.g., flash memory or otherelectrically-programmable-read-only memory configured to form a solidstate drive), volatile memory (e.g., static or dynamicrandom-access-memory), etc. Processing circuitry in control circuitry 20may be used to control the operation of device 10. The processingcircuitry may be based on one or more microprocessors, microcontrollers,digital signal processors, baseband processors, power management units,audio chips, application specific integrated circuits, etc.

Input-output circuitry in device 10 such as input-output devices 22 maybe used to allow data to be supplied to device 10 and to allow data tobe provided from device 10 to external devices. Input-output devices 22may include buttons, joysticks, scrolling wheels, touch pads, key pads,keyboards, microphones, speakers, tone generators, vibrators, cameras,sensors, light-emitting diodes and other status indicators, data ports,etc. A user can control the operation of device 10 by supplying commandsthrough input-output devices 22 and may receive status information andother output from device 10 using the output resources of input-outputdevices 22.

Input-output devices 12 may include one or more displays such as display14. Display 14 may be a touch screen display that includes a touchsensor for gathering touch input from a user or display 14 may beinsensitive to touch. A touch sensor for display 14 may be based on anarray of capacitive touch sensor electrodes, acoustic touch sensorstructures, resistive touch components, force-based touch sensorstructures, a light-based touch sensor, or other suitable touch sensorarrangements.

Control circuitry 16 may be used to run software on device 10 such asoperating system code and applications. During operation of device 10,the software running on control circuitry 16 may display images ondisplay 14.

Display 14 may be a liquid crystal display, an organic light-emittingdiode display, an electrophoretic display, an electrowetting display, adisplay formed from an array of discrete light-emitting diodes formedfrom crystalline semiconductor die, or any other suitable type ofdisplay. Configurations in which display 14 is circular or has at leastone curved edge are sometimes described herein as an example. This is,however, merely illustrative. Any suitable type of display may be usedfor device 10, if desired.

A perspective view of an illustrative electronic device having a displayis shown in FIG. 2. As shown in FIG. 2, device 10 may have a housingsuch as housing 12. Housing 12, which may sometimes be referred to as anenclosure or case, may be formed of plastic, glass, ceramics, fibercomposites, metal (e.g., stainless steel, aluminum, etc.), othersuitable materials, or a combination of any two or more of thesematerials. Housing 12 may be formed using a unibody configuration inwhich some or all of housing 12 is machined or molded as a singlestructure or may be formed using multiple structures (e.g., an internalframe structure, one or more structures that form exterior housingsurfaces, etc.).

Display 14 may be mounted in housing 12. Active area AA of display 14may contain pixels that emit light to form images for viewing by a user.Inactive border area IA does not contain light-emitting pixels. Inactiveborder area IA may have opaque masking structures (e.g., a layer ofblack ink or other opaque masking material on the inner surface of adisplay cover layer or other outer display layer), opaque bezelstructures or other opaque structures that prevent light from passingthrough inactive area IA. Because inactive area IA does not produceimages, display driver circuitry, interconnect lines, and othersupporting circuitry for display 14 may be formed in inactive area IAand may be hidden from view by the opaque structures of inactive areaIA.

In the example of FIG. 2, display 14 has an active area AA with fouredges and four curved (rounded) corners. Other display shapes with oneor more curved edges may be used in forming display 14, if desired. Inthe illustrative configuration for device 10 of FIG. 3, active area AAof display 14 is circular and is surrounded by a ring-shaped inactivearea IA. Display 14 of FIG. 3 is mounted in a housing (housing 12) witha circular footprint. Straps such as straps 16 may be attached tohousing 12 of FIG. 3 (or other housings such as illustrative rectangularhousing 12 of FIG. 2) to support attachment of device 10 to the wrist ofa user (as an example).

FIG. 4 is a diagram of an illustrative display. As shown in FIG. 4,display 14 may include layers such as substrate layer 30. Substratelayers such as layer 30 may be formed from planar circular layers ofmaterial or layers of material with other shapes (e.g., shapes with oneor more curved edges). The substrate layers of display 14 may includeglass layers, polymer layers, composite films that include polymer andinorganic materials, metallic foils, etc.

Display 14 may have an array of pixels 32 for displaying images for auser such as pixel array 34. Pixels 32 in array 34 may be arranged inrows and columns. The edges of array 34 may be curved (i.e., each row ofpixels 32 and/or each column of pixels 32 in array 34 may have adifferent length). There may be any suitable number of rows and columnsin array 34 (e.g., ten or more, one hundred or more, or one thousand ormore, etc.). Display 14 may include pixels 32 of different colors. As anexample, display 14 may include red pixels, green pixels, and bluepixels. If desired, a backlight unit may provide backlight illuminationfor display 14.

Display driver circuitry may be used to control the operation of pixels34. The display driver circuitry may be formed from integrated circuits,thin-film transistor circuits, or other suitable circuitry. The displaydriver circuitry of FIG. 4 includes display driver circuitry 50 andadditional display driver circuitry such as gate driver circuitry 52.Gate driver circuitry 52 may be formed along one or more edges ofdisplay 14. For example, gate driver circuitry 52 may be arranged alongthe left and right sides of display 14 as shown in FIG. 4.

As shown in FIG. 4, display driver circuitry 50 (e.g., one or moredisplay driver integrated circuits, thin-film transistor circuitry,etc.) may contain communications circuitry for communicating with systemcontrol circuitry over signal path 56. Path 56 may be formed from traceson a flexible printed circuit or other cable. The control circuitry maybe located on one or more printed circuits in electronic device 10.During operation, the control circuitry (e.g., control circuitry 20 ofFIG. 1) may supply circuitry such as a display driver integrated circuitin circuitry 50 with image data for images to be displayed on display14. Display driver circuitry 50 of FIG. 4 is located at the top ofdisplay 14. This is merely illustrative. Display driver circuitry 50 maybe located at both the top and bottom of display 14 or in other portionsof device 10.

To display the images on pixels 32, display driver circuitry 50 maysupply corresponding image data to data lines D while issuing controlsignals to supporting display driver circuitry such as gate drivercircuitry 52 over signal paths 54. With the illustrative arrangement ofFIG. 2, data lines D run vertically through display 14 and areassociated with respective columns of pixels 32.

Gate driver circuitry 52 (sometimes referred to as gate line drivercircuitry or horizontal control signal circuitry) may be implementedusing one or more integrated circuits and/or may be implemented usingthin-film transistor circuitry on substrate 30. Horizontal control linesG (sometimes referred to as gate lines, scan lines, emission controllines, etc.) run horizontally through display 14. Each gate line G isassociated with a respective row of pixels 32. If desired, there may bemultiple horizontal control lines such as gate lines G associated witheach row of pixels. The configuration of FIG. 4 in which each gate lineG is associated with a respective row of pixels 32 is merelyillustrative.

Gate driver circuitry 52 may assert control signals on the gate lines Gin display 14. For example, gate driver circuitry 26 may receive clocksignals and other control signals from circuitry 50 and may, in responseto the received signals, assert a gate line signal on gate lines G insequence, starting with the gate line signal G in the first row ofpixels 32 in array 34. As each gate line is asserted, data from datalines D may be loaded into a corresponding row of pixels. In this way,control circuitry such as display driver circuitry 50 and 52 may providepixels 32 with signals that direct pixels 32 to display a desired imageon display 14.

To help minimize the width of inactive border area IA, it may bedesirable to use a data line layout for display 14 in which data linesare folded back on themselves. With this type of arrangement, data linesD each pass multiple times (e.g., two times) through array 34. Becauseeach data line passes through two columns of pixels, the number of datalines in display 14 is minimized and the amount of space needed tointerconnect the data lines in array 34 to display driver circuitry 50within inactive area IA is minimized (particularly in potentialbottleneck areas adjacent to display driver circuitry 50).

A display with folded data lines that help reduce signal line crowdingin this way is shown in FIG. 5. As shown in FIG. 5, display 14 may havesubstrate layers such as layer 30 with a circular outline (e.g., with acircular periphery) and/or with other shapes that have one or morecurved edges. Display driver circuitry 50 may be implemented usingthin-film transistor circuitry and/or integrated circuit(s) on substrate30 and/or on flexible printed circuit 56. Gate driver circuitry 52 maybe located in inactive area IA. Pixels 32 (FIG. 4) may be located inactive area AA.

The data lines in display 14 run vertically through the pixels in activearea AA. In the example of FIG. 5, each data line passes twice throughthe pixels of active area AA. For example, data line D1 has a firstportion such as segment D1-1 that passes vertically upward (in theorientation of FIG. 5) through the pixels of active area AA and a secondportion such as segment D1-2 that passes vertically downward (in theorientation of FIG. 5) through the pixels of active area AA. SegmentsD1-1 and D1-2 may pass through different respective halves of activearea AA. Data line D1 also has a portion such as segment D1-3 (i.e., acurved coupling segment) in inactive area IA that couples data lineportion D1-1 to data line portion D1-2. As another example, data line D2(which starts near the center of display 14 and which folds back onitself to the left) has first portion D2-1 and second portion D2-2 thatare coupled by portion D2-3 in inactive area IA. Because data lines D indisplay 14 such as illustrative data lines D1 and D2 each fold back onthemselves, fewer data lines (half as many) are present in potentialbottleneck regions in active area IA (e.g., portions of inactive area IAnear display driver circuitry 50A such as regions 60).

The gate line conductor in each row of pixels may be bisected to ensurethat all pixels 32 in array 34 can be addressed (i.e., to ensure thateach pixel can be independently loaded with a desired data value). Theleft half of each gate line conductor overlaps one half of the foldeddata line (e.g., the half of the data line in the left half of area AA)and the right half of each gate line conductor in the same row overlapsthe other half of the folded data line (i.e., the half of the data linein the right half of area AA).

To accommodate the curved shape of the peripheral edge of substrate 30,the gate lines G in display 14 may be shorter near the upper and loweredges of display 14 and may be longer near the middle of display 14.Gate lines G may be provided with gate line signals from gate drivercircuitry 52. With one illustrative arrangement, gate driver circuits onthe left and right sides of display 14 assert gate line signals G in analternating fashion on the left and right gate lines segments of eachgate line conductor. For example, gate lines signals may be asserted ongate line segment G1 on the left of display 14, gate line segment G2 inthe same row of pixels on the right side of display 14, gate linesegment G3 on the left of display 14 in a subsequent row of pixels, gateline segment G4 in the same row of pixels on the right side of display14, and so forth. Other patterns may be used when asserting gate linesignals, if desired.

FIG. 6 is a diagram showing how gate lines in each row may be dividedinto a left half (Gate[2]. . . Gate[n+1]) and a corresponding right half(Gate[1]. . . Gate[n]). In the arrangement of FIG. 6, the portions ofthe data lines that extend vertically upward through the display havedifferent lengths than the corresponding folded segments of the samedata lines that extend vertically downwards through the display. Thismay create uneven data lines with different lengths and thereforedifferent amounts of loading. If desired, folded data lines may bearranged in display 14 so that the first and second parallel verticalsegments of each folded data line are equal in length (i.e., so that thesegments that extend upwards have the same length as the segments thatextend downwards, as shown in FIG. 7). The arrangement of FIG. 7 mayhelp ensure that all data lines experience the same amount of loading.

If desired, the number of data lines that traverse potential bottleneckregions 60 may be minimized by supplying data signals to the pixels ofdisplay 14 using display driver circuitry that is located on the top andbottom of display 14. This type of arrangement is shown in FIG. 8. Asshown in FIG. 8, pixels 32 in array 34 may be arranged in an upper halfarray (upper array portion 34T) and a lower half array (lower arrayportion 34B). Gate driver circuitry 52LT on the left of upper arrayportion 34T and gate driver circuitry 52RT on the right of upper arrayportion 34T may be coupled to the gate lines G in upper array portion34T. Gate driver circuitry 52LB on the left of lower array portion 34Band gate driver circuitry 52RB on the right of lower array portion 34Bmay be coupled to the gate lines in lower array portion 34B. Displaydriver circuitry 50T, which is located along the top portion of display14, may be used to supply data signals to data lines D in upper arrayportion 34T and may supply control signals to gate driver circuitry 52LTand 52RT. Gate driver circuits 52LT and 52RT may respectively handle oddand even gate lines G in upper array portion 34T. Display drivercircuitry 50B, which is located adjacent to lower array portion 34Balong the lower edge of display 14, may be used to supply data signalsto data lines D in lower array portion 34B and may supply controlsignals to gate driver circuitry 52LB and 52RB. Gate driver circuits52LB and 52RB may respectively handle odd and even gate lines G in lowerarray portion 34B.

If desired, the data lines in upper array portion 34T may be folded andthe gate lines G in upper array portion 34T may be segmented into leftand right halves handled by circuits 52LT and 52RT, respectively. Thelower portion of display 14 may also use folded data lines and segmentedgate lines if desired.

FIG. 9 is a perspective view of a portion of flexible printed circuit 56showing how printed circuit 56 may include metal signal traces 56-1 andflexible polymer substrate 56-2. Flexible printed circuit 56 may bendabout bend axis 70 during use of display 14 in device 10. Portions offlexible printed circuit 56 may, for example, extend between housing 12and strap 16, which may allow flexible printed circuit 56 to bend asstrap 16 is wrapped around the wrist of a user or it be desirable tobend flexible printed circuit 56 (by 90° or 180° or more) to accommodatemounting of flexible printed 56 within device 10 (whether or notportions of flexible printed circuit 56 extend into straps 16).

Flexible printed circuit 56 may have one or more layers of substratematerial and/or encapsulant layers to help reduce stress in metal traces56-1 (e.g., to adjust the location of the neutral stress plane forprinted circuit 56 to lie within traces 56-1). Traces 56-1 may also haveserpentine shapes or other shapes that help enhance trace flexibilityand reduce the likelihood of cracking during bending. Traces such astraces 56-1 may have a pitch of 20-25 microns, 10-50 microns, more than10 microns, less than 30 microns, etc. The minimum spacing betweenadjacent traces 56-1 may be 2-5 microns, more than 1 micron, less than10 microns, etc. The wavelength of each trace 56-1 may be about 30-50microns, less than 60 microns, more than 20 microns, or other suitablewavelength and each trace may have curved portions characterized by acircular radius of 5-10 microns, more than 4 microns, less than 15microns, etc. The width of each trace 56-1 may be about 3-8 microns,more than 2 microns, less than 10 microns, etc.

FIGS. 10 and 11 show illustrative patterns that may be used for traces56-1 on substrate 56-2. In the arrangement of FIG. 10, traces 56-1follow sinewave-like meandering paths. In the arrangement of FIG. 11,traces 56-1 each have a series of straight segments and semicircularsegments. Other layouts may be used for traces 56-1 if desired. Theconfigurations of FIGS. 9, 10, and 11 are merely illustrative.

FIG. 12 is a circuit diagram of gate driver circuitry 52. Gate drivercircuitry 52 may have the shape of a curved strip of circuitry ininactive area IA that follows the curved edge of array 34. Circuitry 52may include shift register circuitry formed from a chain of registerssuch as registers 52-1. The output of each register may serve both as agate line signal for a corresponding gate line G and as a trigger signalfor a subsequent register in the chain of registers. Output drivers 52-2(sometimes referred to as output buffers) may be used to strengthen theoutput of each register and to apply the strengthened version of theregister output to a corresponding gate line G.

The rise and fall times of the gate line signals on gate lines G willtend to be lengthened with increasing gate line length and will tend tobe decreased with increasing output driver size. Gate line loadingeffects (which cause rise and fall times to be extended) increase withincreasing gate line length, so longer rows in array 34 that experiencemore loading than shorter rows will experience lengthened gate linesignal rise and fall times. To compensate for the additional loadingexperienced when asserting gate line signals in longer rows, thestrength of output drivers 52-2 can be progressively increased as afunction of increasing gate line length. This type of arrangement isshown in FIG. 13.

As shown in the example of FIG. 13, gate driver circuitry 52 includesmultiple gate line drivers 52-2. The strength of the driver in row R2,which has a longer gate line than row R1 is greater than the strength ofthe driver in row R1. Similarly, the strength of the driver in row R3,which has a gate line that is longer than the gate line in row R2 islarger than the strength of the driver in row R2. By usingcorrespondingly larger output buffers 52-2 for longer (more heavilyloaded) gate lines G, the gate line signals on all gate lines may bemade to have substantially similar shapes (e.g., the rise and fall timeswill all be satisfactory even in displays with curved edges such asdisplays with circular pixel arrays 34).

The foregoing is merely illustrative and various modifications can bemade by those skilled in the art without departing from the scope andspirit of the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

What is claimed is:
 1. A display, comprising: display driver circuitry;data lines coupled to the display driver circuitry; gate lines coupledto the display driver circuitry; and an array of pixels, wherein thepixels receive data from the display driver circuitry over the datalines and are controlled with control signals received from the displaydriver circuitry over the gate lines, wherein the data lines are foldeddata lines and wherein each folded data line has a first verticalsegment that supplies data to a first column of the pixels in the arrayand has a second vertical segment that is coupled to the first verticalsegment and that supplies data to a second column of the pixels in thearray.
 2. The display defined in claim 1 wherein the array of pixels hasa curved edge.
 3. The display defined in claim 2 wherein the array ofpixels comprises a circular array of pixels.
 4. The display defined inclaim 1 wherein the display has an active area in which the array ofpixels displays images and has an inactive area that does not containany of the pixels and wherein at least some of the display drivercircuitry is located in the inactive area.
 5. The display defined inclaim 4 wherein each data line has a coupling segment in the inactivearea that couples the first vertical segment of that data line to thesecond vertical segment of that data line.
 6. The display defined inclaim 5 wherein the coupling segment of each data line is curved.
 7. Thedisplay defined in claim 6 wherein the array of pixels comprises acircular array of pixels.
 8. The display defined in claim 7 wherein thepixels in the array include rows of pixels each of which is controlledby gate lines signals from a corresponding one of the gate lines,wherein the gate line in each row is divided into a first segment thatcontrols a first half of the pixels in that row and a second half thatcontrols a second half of the pixels in that row.
 9. The display definedin claim 8 wherein the inactive area is a ring-shaped area thatsurrounds the active area.
 10. The display defined in claim 1 whereinthe display driver circuitry includes a shift register having an outputdriver in each row of pixels that supplies a gate line signal to thegate line in that row of pixels.
 11. The display defined in claim 10wherein the array of pixels has a curved edge and is surrounded by aring-shaped inactive area and wherein the shift register forms part of agate driver circuit that extends along the curved edge in a curved stripunder the ring-shaped inactive area.
 12. The display defined in claim 1wherein the first and second vertical segments of at least some of thedata lines are of different lengths.
 13. The display defined in claim 1wherein the first and second vertical segments of each data line are ofequal length.
 14. The display defined in claim 1 wherein the gate lineof each row includes a left half that supplies the control signals to aleft half of the pixels in that row and a right half that is isolatedfrom the left half and that supplies the control signals to a right halfof the pixels in that row.
 15. The display defined in claim 1 whereinthe array of pixels has left and right halves and wherein the firstvertical segment in at least a given one of the folded data lines is inthe left half and the second vertical segment of the given one of thefolded data lines is in the right half.
 16. The display defined in claim15 wherein the array of pixels is divided into halves and wherein thefirst vertical segment of each of the folded data lines is in adifferent one of the halves than the second vertical segment of thatfolded data line.
 17. A display, comprising: a circular array of pixels;display driver circuitry; folded vertical data lines each of whichsupplies data signals from the display driver circuitry to first andsecond columns of the pixels; and horizontal lines that supply controlsignals to rows of the pixels.
 18. The display defined in claim 17wherein each row of pixels is supplied with control signals by arespective one of the horizontal lines and wherein the horizontal linethat supplies the control signals to that row of pixels has a left halfthat supplies the control signals to a left half of the pixels in thatrow and a right half that is isolated from the left half and thatsupplies the control signals to a right half of the pixels in that row.19. A display, comprising: a circular array of pixels; display drivercircuitry; data lines each of which has a first segment, second segmentthat runs parallel to the first segment, and a coupling segment thatcouples the first and second segments together, wherein the firstsegment supplies data signals from the display driver circuitry to afirst column of the pixels and wherein the second segment supplies datasignals from the display driver circuitry to a second column of thepixels; and horizontal lines that supply control signals to rows of thepixels.
 20. The display defined in claim 19 wherein each row of pixelsis supplied with control signals by a respective one of the horizontallines, wherein the horizontal line that supplies the control signals tothat row of pixels is divided into electrically isolated left and rightsegments, wherein the left segment supplies the control signals to aleft half of the pixels in that row, and wherein the right segmentsupplies the control signals to a right half of the pixels in that row.